The present invention relates to a cushioning fender adapted to be mounted on one or both of the hull of a ship and a shore installation, such as a pier, whart, quay, dock, float or the like impact receiving structure, for cushioning the impact of the ship against the shore installation.
Various types of elastically deformable fenders have long been used to cushion the impact of the ship against the shore installation for protecting both the boardside of the ship and the shore installation. Of these elastically deformable fenders, two types of substantially cup-shaped fenders are also known. By way of example, the Japanese Utility Model Publication No. 49-1190, published on Jan. 12, 1974, discloses a substantially cup-shaped fender of a construction shown in FIG. 1 of the accompanying drawings and the Japanese Patent Publication No. 49-37399, published on Oct. 8, 1974, discloses a substantially cup-shaped fender of a construction shown in FIG. 2 of the accompanying drawings.
Referring first to FIG. 1, the fender disclosed in the first mentioned publication comprises a substantially cup-like body of one-piece construction made of an elastic material and constituted by a substantially frusto-conical hollow wall 100 and a substantially cylindrical hollow wall 101 having one annular end connected to a radially outwardly enlarged annular end of the frust-conical hollow wall 100 and the other annular end formed integrally with a radially outwardly extending fitting flange 102. This fender is so designed that, when an external load is applied thereto from, for example, the ship approaching the shore installation through a radially inwardly reduced annular end of the frusto-conical hollow wall 100 in a direction substantially perpendicular to the plane of said reduced annular end of the frusto-conical hollow wall 100, the fender body can be collapsed or compressed inwardly in a direction close towards the shore installation after having been buckled radially outwardly about the buckling point defined at the boundary between the frusto-conical hollow wall 100 and the cylindrical hollow wall 101, to such an extend as shown by the broken line in FIG. 1.
The first mentioned publication further discloses that, in order to render the fender to exhibit its optimum performance, the fender is required to satisfy the following requirements.
h=0.1H to 0.3H, PA1 Da=0.9 to 1.5H, and PA1 Db=0.50H to 0.85H
wherein h represents the height of the cylindrical hollow wall 101 as measured from the plane of a surface of contact of any one of the fitting flanges 102 to the shore installation to the boundary between the frusto-conical hollow wall 100 and the cylindrical hollow wall 101, H represents the overall height of the fender body, Da represents the outer diameter of the cylindrical hollow wall 101 and Db represents the outer diameter of the radially inwardly reduced annular end of the frusto-conical hollow wall 100 opposite to the cylindrical hollow wall 101.
On the other hand, the fender of the construction shown in FIG. 2 is substantially disclosed in the second mentioned publication and comprises an annular fender body, generally designated by 110, of one-piece construction made of an elastic material and having a substantially V-shaped cross section defined by a buffer block 111, occupying the bottom of the shape of a figure "V", outside and inside support walls 112 and 113 respectively occupying the two lateral sides of the shape of the figure "V", and outwardly and inwardly extending fitting flanges 114 and 115 opposite to the buffer block 111 and on one side of the respective support walls 112 and 113 remote from said buffer block 111. The buffer block 111 has a flat impact receiving surface defined at 111a, the plane of which is in parallel to the plane of a surface of contact of any one of the annular outside and inside fitting flanges 114 and 115 to the shore installation to which the fender is fitted, and a pair of opposed side faces held in flush with outer faces of the respective support walls 112 and 113 which extend so as to diverge from each other in a direction away from the buffer block 111.
Although any one of the prior art fenders respectively disclosed in the first and second mentioned publications appears to function satisfactorily and effectively, the energy absorbing characteristic thereof is still low.